Fan-Controller-system

embedded project using Atmega32 created by bassant amr in this project we control speed of fan (motor) depenent on temperature degree if temp < 30c => the fan is off else the fan is on in specific speed depend on reading of temp if temp >= 120c => the fan will rotate by maximuim speed else if temp >= 90 => the fan will rotate by 75% from maximuim speed else if temp >= 60 => the fan will rotate by 50% from maximuim speed else if temp >= 30 => the fan will rotate by 25% from maximuim speed

microcontroller

in this project we will use ATmega32 which have 4 port and 8 pins for each port

Temperature sensor

we need to use LM35 temp sensor which return analog value (0-5v) connected to PA2 (PORT A - PIN_num 2) (channel 2)

10 bit ADC

we need to use 10-bit ADC (analog to digital converter) to convert analog input from LM35 into digital value (0-1023) in atmega32 we have 8 pins (PORT A) analog and one ADC which can convert only one channel at a time

FAN (DC-Motor)

the aim of this project is to enable fan based on temperature so we need DC-Motor which will act as fan but before this we need to use H-bridge chip which control two importand parameter of DC-motor first is speed. we can control speed of Motor by apply different voltages Level (0-5v in our case) second parameter is direction of rotate controlled by polarity of volt ( + / - ) L293D (H-brige chip used ) connected to microcontroller on 3 pins PB0 & PB1 to control rotate direction and PB3 to apply PWM with different duty cycle. the chip will take average vale of PWM and apply it to dc motor

PWM

we generate PWM(Pulse Width Modulation) with different duty cycles to control speed of motor if we have in our case PWM with duty cycle -> 0% = avr voltage = 0 -> 25% = avr voltage 1.25 apply to dc motor -> 50% = avr voltage 2.5 apply to dc motor -> 75% = avr voltage 3.75 -> 100% = avr voltage 5v

LCD

we need to use 16X2 8-bit mode LCD to display two lines -> first: state of fan (ON - OFF) -> second: sensor reading (temp) we connect data path to PORTC RS -> PD0 E -> PD1 R/W & VSS -> GND VDD -> 5v